Human skin fibroblast cultures will be utilized to examine the detailed steps in the normal biosynthesis of collagenase. In addition, cell cultures will be employed to characterize the nature of the modulatory effect of steroid hormones on collagenase synthesis and/or secretion. Since both in vivo and in vitro studies show an increased amount of collagenase in patients with recessive dystrophic epidermolysis bullosa, we will attempt to purify collagenase from recessive dystrophic epidermolysis bullosa fibroblast cultures to homogeneity. These studies will enable us to perform detailed structural and kinetic analyses on the putatively mutant enzyme.